Physical layer design for uplink (UL) multiuser multiple-input, multiple-output (MU-MIMO) in wireless local area network (WLAN) systems

An apparatus for handling residual frequency offset error, comprising:

• a receiver configured to receive a packet having a preamble portion comprising tone-interleaved long training fields (LTFs) having interleaved tones designated for each spatial stream of each user in an uplink (UL) multiuser (MU) transmission, wherein in each tone-interleaved LTF, a first spatial stream is associated with a first subset of tones and a second spatial stream is associated with a second subset of the tones interleaved with the first subset of the tones, wherein the interleaved tones are arranged in a pattern, and wherein the pattern is shifted between two consecutive tone-interleaved LTFs;
• and
• a processing system configured to perform frequency offset adjustment on the packet based on the tone-interleaved LTFs.

An apparatus for handling residual frequency offset error, comprising:

• means for receiving a packet having a preamble portion comprising tone-interleaved long training fields (LTFs) having interleaved tones designated for each spatial stream of each user in an uplink (UL) multiuser (MU) transmission, wherein in each tone-interleaved LTF, a first spatial stream is associated with a first subset of tones and a second spatial stream is associated with a second subset of the tones interleaved with the first subset of the tones, wherein the interleaved tones are arranged in a pattern, and wherein the pattern is shifted between two consecutive tone-interleaved LTFs;
• and
• means for performing frequency offset adjustment on the packet based on the tone-interleaved LTFs.